Electronic devices are increasingly enabling users to locate information in different ways. For example, a user wanting information about an item such as a book can perform a search to locate information about the book, or can navigate through the Website of an online retailer to locate a page of information about the book. In addition, a user can capture an image of a copy of the book using a camera of a portable computing device and cause that image to be matched against a database of images in order to identify the item and provide the user with information about that item. In addition to providing this information, applications can also suggest related items in which the user might be interested. The algorithms used to determine these items typically rely upon objective criteria, such as books by the same author or in the same category, and are unable to take into account what a user might subjectively think to be a related item, or which aspects of an item are most important in determining similarity.